Youngs Modulus problem - Grrr

Heres my problem.
Youngs modulus for lead: 1.6exp10 N/m^2. Density of Lead: 11,4g/cm^3.
Mass of one mole lead: 207g
Model the interactions as if they were connected by springs.
Determine distance between lead atoms and approx spring constant.

Easy enough Y= K/d But what is bugging me is d. dia of atom
How do you determine d from density and the mass of one mole?
And how do u relate it to the distance between atoms?
It is keeping me up.
Probably very easy but just not seeing it.